🔬 Astrophysics Trivia Questions & Answers
Black holes, the Big Bang and the physics of the cosmos. Below are 30 free astrophysics trivia questions with answers — part of Science trivia on BUZZ. Want a real challenge that adapts to what you know? Play the Science quiz — no signup needed to start.
30 Astrophysics trivia questions
Q1. A star far more massive than the Sun can collapse at the end of its life into what?
Answer: A black hole
💡 Stars over roughly 20 times the Sun's mass can leave a black hole behind after a supernova.
Q2. What planet is known as the Red Planet?
Answer: Mars
💡 Mars appears red because its surface is covered in iron oxide — essentially rust.
Q3. Which planet has the most moons?
Answer: Saturn
💡 Saturn has over 140 confirmed moons as of 2024, surpassing Jupiter.
Q4. What planet is closest to the Sun?
Answer: Mercury
💡 Despite being closest to the Sun, Mercury is not the hottest planet — Venus is, due to its thick atmosphere.
Q5. How long does light from the Sun take to reach Earth?
Answer: About 8 minutes
💡 If the Sun suddenly disappeared, Earth would continue to orbit its current position for about 8 minutes.
Q6. What is the closest star to Earth after the Sun?
Answer: Proxima Centauri
💡 Proxima Centauri is about 4.24 light-years away and is part of the Alpha Centauri triple-star system.
Q7. What is the name of the first artificial Earth satellite launched by the USA?
Answer: Explorer 1
💡 Explorer 1 was launched in January 1958, four months after Sputnik 1. It discovered the Van Allen radiation belts surrounding Earth.
Q8. Stars spend most of their lives in which stable, hydrogen-burning phase?
Answer: The main sequence
💡 The Sun is roughly halfway through its 10-billion-year main-sequence lifetime.
Q9. What colour are the very hottest stars, blazing at up to 40,000 degrees?
Answer: Blue
💡 Cool stars glow red at around 3,000 K, while the hottest shine blue-white.
Q10. What is the general name for a vast cloud of gas and dust where new stars are born?
Answer: Nebula
💡 The word nebula is Latin for cloud or mist.
Q11. How many bones are in the adult human body?
Answer: 206
💡 Babies are born with around 270-300 bones, but many fuse together as they grow.
Q12. Which Bell Labs engineer founded radio astronomy in 1932 by tracing a mystery hiss to the galaxy?
Answer: Karl Jansky
💡 He mounted his antenna on four Ford Model T tires so he could rotate it, and the radio-brightness unit astronomers still use today is named the jansky in his honor.
Q13. Measuring a star's distance via its shift against background stars as Earth orbits is called what?
Answer: Parallax
💡 The effect is the same trick your eyes use for depth perception, just stretched across the width of Earth's entire orbit instead of the gap between your eyes.
Q14. What term describes Type Ia supernovae, whose steady brightness gauges cosmic distances?
Answer: Standard candles
💡 Because their peak brightness is so consistent, comparing how dim one looks from Earth tells astronomers almost exactly how far away it is.
Q15. Identifying a distant star's elements from the dark lines in its light spectrum is called what?
Answer: Spectroscopy
💡 Each element absorbs light at its own specific wavelengths, so those dark gaps in a star's rainbow work like a chemical fingerprint.
Q16. LIGO splits a laser down two long tunnels; what passing through stretches and shifts the beams?
Answer: A gravitational wave passing through
💡 The stretching LIGO measures is almost absurdly tiny, smaller than the width of a proton, which is why the detectors have to be so enormous just to catch it.
Q17. How old is the universe, approximately?
Answer: 13.8 billion years
💡 The Big Bang occurred approximately 13.8 billion years ago, according to cosmic microwave background measurements.
Q18. What ultra-dense core is left when a massive star's centre collapses in a supernova?
Answer: A neutron star
💡 A neutron star crams more mass than the Sun into a ball roughly the size of a city.
Q19. The Hertzsprung-Russell diagram sorts stars by luminosity against which property?
Answer: Surface temperature
💡 On the H-R diagram, most stars fall along a diagonal band called the main sequence.
Q20. Light from a star racing toward Earth gets shifted toward which end of the spectrum?
Answer: The blue end
💡 The Andromeda galaxy is blueshifted because it is heading toward the Milky Way.
Q21. A star stays stable when its outward radiation pressure balances which inward pull?
Answer: Gravity
💡 This lifelong tug-of-war is called hydrostatic equilibrium and keeps a star's shape steady.
Q22. The faint cosmic microwave background is the leftover glow from which event?
Answer: The Big Bang
💡 This afterglow now sits just 2.7 degrees above absolute zero, stretched cool by cosmic expansion.
Q23. Vera Rubin found outer galaxy stars orbit as fast as inner ones — impossible unless what is true?
Answer: The galaxy has far more unseen mass
💡 Rubin's rotation-curve measurements across dozens of galaxies became the strongest observational case that dark matter exists.
Q24. Which astronomer coined 'dark matter' in 1933 after the Coma cluster lacked enough mass?
Answer: Fritz Zwicky
💡 The astronomical community was so dismissive of his idea that Zwicky himself later described their reaction as openly hostile.
Q25. Trying to kill an antenna hiss in 1964, Penzias and Wilson first blamed it on what?
Answer: Pigeon droppings inside the antenna
💡 They climbed up and scrubbed the antenna clean, but the mysterious hiss stayed exactly the same, because it was radiation left over from the Big Bang itself.
Q26. In 1967, a grad student nicknamed a regular radio pulse 'LGM-1' — what did LGM stand for?
Answer: Little Green Men
💡 That student, Jocelyn Bell Burnell, had actually found the first pulsar, a rapidly spinning neutron star, and the 1974 Nobel Prize for the discovery went to her supervisor instead.
Q27. In 1800, what simple instrument helped Herschel discover light beyond the rainbow's red end?
Answer: A thermometer
💡 He noticed the thermometer registered a higher temperature just past visible red than anywhere inside the rainbow itself, revealing what we now call infrared radiation.
Q28. Annie Jump Cannon sorted stars by temperature into a scheme taught via which string of letters?
Answer: OBAFGKM
💡 At her fastest, Cannon could classify a star roughly every two to three minutes just by eye, using a lightbox and a magnifying glass.
Q29. In 1998, two teams studying Type Ia supernovae made which Nobel-winning discovery?
Answer: The expansion is speeding up
💡 The mysterious force behind that acceleration got a placeholder name that stuck: dark energy.
Q30. Which Belgian priest-physicist proposed in 1927 that the universe began as a 'primeval atom'?
Answer: Georges Lemaitre
💡 His idea became the seed of what we now call the Big Bang theory, proposed years before Edwin Hubble's observations gave it solid evidential backing.
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